Triangle of numbers read by rows, T(n, k) = (n*(n-1))*Stirling2(k, 2), for n >= 1 and 1 <= k <= n.

Terms

a(0) =0a(1) =0a(2) =2a(3) =0a(4) =6a(5) =18a(6) =0a(7) =12a(8) =36a(9) =84a(10) =0a(11) =20a(12) =60a(13) =140a(14) =300a(15) =0a(16) =30a(17) =90a(18) =210a(19) =450a(20) =930a(21) =0a(22) =42a(23) =126a(24) =294a(25) =630a(26) =1302a(27) =2646a(28) =0a(29) =56